Hackers brew self-destruct code to counter police forensics

Hackers have released an application designed to thwart a Microsoft-packaged forensic toolkit used by law enforcement agencies to examine a suspect's hard drive during a raid.

The hacker tool, dubbed DECAF, is designed to counteract the Computer Online Forensic Evidence Extractor, aka COFEE. The latter is a suite of 150 bundled, off-the-shelf forensic tools that run from a script. Microsoft combined the programs into a portable tool that can be used by law enforcement agents in the field before they bring a computer back to their forensic lab. The script runs on a USB stick that agents plug into the machine.

The tools scan files and gather information about activities performed on the machine, such as where the user surfed on the internet or what files were downloaded.

Someone submitted the COFEE suite to the whistleblower site Cryptome last month, prompting Microsoft lawyers to issue a take-down notice to the site. The tool was also being distributed through the BitTorrent file-sharing network.

This week two unnamed hackers released DECAF, an application that monitors a computer for any signs that COFEE is operating on the machine.

According to the Register, the program deletes temporary files or processes associated with COFEE, erases all COFEE logs, disables USB drives, and contaminates or spoofs a variety of MAC addresses to muddy forensic tracks.

The hackers say that later releases of the program will allow computer owners to remotely lock down their machine once they detect that it has fallen into law enforcement hands. The hackers, however, have not released source code for the program, which would make it easy for anyone to see if the program contains malware that might also harm a computer or allow the attackers to take control of it.

Update: The developers of DECAF have taken issue with Wired referring to them as hackers. "We're just two developers who support the free flow of information and privacy," one of them wrote in an anonymous e-mail to Wired. "You could say we're just average joes."